O, o-bis(4-nitrophenyl) alkanephosphonates



Patented Feb. 9, 1954 o,o-B1s(4-NrriioeHENY-L) ALKANE- PHOSPHONATESHenry Tolkmlth, Midland, Mich., assigngr to The Dow Chemical Company,Midland, Mich a corporation of Delaware No Drawing. Application April21, 1953, Serial No. 350,229

3 Claims. 1 The present invention is directed to the 0,0- bis-(l-nitrophenyl) alkanephosphonates of the In this and succeeding formulaeR represents methyl or ethyl. These compounds are crystalline solids,somewhat soluble in many organic solvents and substantially insoluble inwater. They are of value as intermediates for the preparation of morecomplex phosphorus derivatives and as toxic constituents of parasiticidecompositions.

The new compounds may be prepared by reacting two molecular proportionsof 4-nitrophenol with one molecular proportion of an alkanephosphonicdichloride of the formula:

in an inert organic solvent such as diethyl ether or benzene. Thereaction is carried out in the presence of a hydrogen chloride acceptorsuch as pyridine.

In carrying out the reaction, the 4-nitrophenol and pyridine aredispersed in the solvent and the resulting mixture added portionwisewith stirring to the alkanephosphonic dichloride dispersed in the samesolvent. Upon completion of the contacting of the reactants, the mixtureis heated at a temperature of from 35 to 80 C. fora short period of timeto complete the reaction. The reaction is somewhat exothermic and takesplace smoothly at the temperature range of from 30 to 80 C. Thetemperature may be controlled by regulation of the rate of contactingthe reactants and by the addition or subtraction of heat, if required.Upon completion of the reaction, the mixture may be filtered and thefiltrate distilled under reduced pressure at gradually increasingtemperatures to separate low boiling constituents and to obtain as aresidue the desired 0,0-bis(4-nitrophenyl) alkanephosphonate.Distillation temperatures substantially in excess of 100 C. for anyappreciable period of time should be avoided as the desired productshave a tendency to decompose at such temperatures.

Ezcmplc 1.0,0 bis(4 nitrophenyl) methanephosphonate 32.7 grams (0.236mole of 4-nitrophenol and 2 22 grams (0.278 mole) of pyridine weredispersed in 200 milliliters of diethyl ether and the resulting mixtureadded portionwise with stirring to 15.3 grams (0.115 mole) ofmethanephosphonic dichloride (having a boiling point of 163 C. atatmospheric pressure) dispersed in 200 milliliters of diethyl ether. Theresulting mixture was thereafter heated for 3 hours at the boilingtemperature and under reflux to complete the reaction. The reactionproduct was then filtered and the filtrate distilled under reducedpressure to a temperature up to C. to obtain as a residue 0,0 bis(4nitrophenyl) methanephosphonate. The latter is a crystalline solidmelting at C.

Example 2.0,0-bis(ll-nitrophengl) ethanephosphonate 32.7 grams (0.236mole) of l-nitrophenol and 22 grams (0.278 mole) of pyridine weredispersed in 200 milliliters of diethyl ether and the resulting mixtureadded portionwise with stirring to 17 grams (0.115 mole) ofethanephosphonic dichloride (having a boiling point of C. at atmosphericpressure) dispersed in 200 milliliters of diethyl ether. The mixture wasthereafter heated for 3 hours at the boiling temperature and underreflux to complete the reaction. At the end of this period, the reactionproduct was filtered and the filtrate concentrated by distillation underreduced pressure to a temperature up to 55 C. to obtain as a residue0,0-bis-(4-nitrophenyl) ethanephosphonate. The latter is a crystallinesolid melting at 138 C.

The new 0,0-bis(4-nitrophenyl) alkanephosphonate products are effectiveas parasiticides and adapted to be employed for the control of a widerange of agricultural and household pests such as flies, mites, aphids,beetles, cockroaches and Southern army worms. For such use, thecompounds may be dispersed in an inert finely divided solid and employedas a dust. Also, such mixtures may be dispersed in water with the aid ofa dispersing and wetting agent and the resulting aqueous suspensionsemployed as sprays. In other procedures, the new products may beemployed in oils, as constituents in oil-in-water emulsions, or in waterdispersion with or without the addition of emulsifying, wetting ordispersing agents. Suitable concentrations of the toxicants in dusts arein the order of from about 0.1 to 10 percent by weight of the dust andin liquid suspensions from about 0.1 to 3 pounds per 100 gallons of thespray mixture. In operations illustrative of the effectiveness of thenew compounds, 100 percent kills of two-spotted spider mites and Mexicanbean beetles were obtained with aqueous spray compositions containing0.5 and 1.0 pound, respectively, of the toxic 0,0bis(4-nitrophenyl)methanephosphonate per 100 gallons of spray mixture.

This is a. continuation-in-part of my copending application Serial No.203,756, filed December 30, 1950.

I claim:

1. An 0,0 bis(4 nitrophenyl) .alkanephosphonate of the formula 4 whereinR represents a member of the group consisting of methyl and ethyl.

2. 0,0 bisOi nitrophenyl methanephosphonate.

HENRY TOLKMITH.

No references cited.

1. AN O,O - BIS(4 - NITROPHENYL) ALKANEPHOSPHONATE OF THE FORMULA